No I don't think WII will have more users than the PS3. Only hardcore gamers usually buy more than one console, and as you have said a few posts before this one, they are not very numerous. PS3 will definitely be peoples first choice, because it has far greater 3rd party support and except for Japan, Nintendo can't match Sony in terms of the games being released for its consoles.
I think Nintendo has done a smart thing, being unable to match MS and Sony in resources and clout over hardware vendors, instead of making yet another "killer" console, they've gone for gameplay and will be making a nice bundle of money since it makes its own games instead of relying excessively on 3rd party support. The Wii seems to be a move aimed at consolidating Nintendo's position in the market, and repositioning its image so as to avoid direct confrontation with Sony and MS, hence the lower price.
I think Nintendo has done a smart thing, being unable to match MS and Sony in resources and clout over hardware vendors, instead of making yet another "killer" console, they've gone for gameplay and will be making a nice bundle of money since it makes its own games instead of relying excessively on 3rd party support. The Wii seems to be a move aimed at consolidating Nintendo's position in the market, and repositioning its image so as to avoid direct confrontation with Sony and MS, hence the lower price.